The Legendary Dresden Green Diamond

An Important Exhibition of Seven Rare Gem Diamonds

“…on these stones for future researchers, and that the opportunity will become available to provide similar reports on other named pieces as we seek to learn more about these touchstones of gemology." Since then, Gems & Gemology has published gemological reports on the Hope Diamond (Crowningshield, 1989), the Dresden Green (Kane et al, 1990), and, most recently, the 128 ct Star of the South (Smith and Bosshart, 2002). The information on the seven diamonds discussed here represents a continuation of this kind of documentation for gemologists and the public.…”

“…Natural blue-green to green color in diamonds is the result of exposure to radiation in the earth and the subsequent formation of radiationinduced color centers. In nature, such radiation is typically alpha or beta; the limited penetrating ability of these particles is the reason most rough "green" diamonds have only a thin "skin" of color (Kane et al, 1990). A saturated body color can only be produced by high-energy penetrating radiation such as gamma or neutron, and in nature such sources are very rare, though they are easily produced in a nuclear reactor (Ashbaugh, 1989).…”

“…Furthermore, these colors tend to be unstable to heat. For a diamond to acquire a saturated green or blue-green body color in nature, it must remain close to a gamma or neutron source for thousands if not millions of years without being exposed to excessive heat (Ashbaugh, 1989;Kane et al, 1990). It is this very rare set of conditions that makes a diamond like the Ocean Dream almost unique.…”

“…Determining the cause of blue-green colornatural or altered-is challenging, as both situations produce similar gemological features (Kane et al, 1990). In addition, important identification criteria may be lost during the process of faceting the diamond, because of the shallowness of the green surface layer typically produced by natural radiation exposure (see Crowningshield, 1963).…”

Iridescence in Metamorphic "Rainbow" Hematite

“…The largest and most famous green diamond is the 41 ct Dresden Green (figure 6), sourced from the Golconda mines in India sometime before its earliest historical record in 1722 (Hough, 1913;Rosch, 1957;Bosshart, 1989Bosshart, , 1994Kane et al, 1990;Astric et al, 1994;Morel, 1994). Several other famous green diamonds have been sold in recent years, including the 5.51 ct blue-green Ocean Dream (mined in the Central African Republic), the 25 ct Gruosi Green (South Africa and never graded by GIA), and the 5.03 ct Aurora Green (Brazil), which sold at auction in 2016 for more than US $3.3 million per carat (De-Marco, 2016).…”